| Document and Entity Information | Sep. 03, 2019 |
| Cover [Abstract] | |
| Entity Registrant Name | ENCORE WIRE CORP |
| Amendment Flag | false |
| Entity Central Index Key | 0000850460 |
| Document Type | 8-K |
| Document Period End Date | Sep. 3, 2019 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 000-20278 |
| Entity Tax Identification Number | 75-2274963 |
| Entity Address, Address Line One | 1329 Millwood Road |
| Entity Address, City or Town | McKinney |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75069 |
| City Area Code | (972) |
| Local Phone Number | 562-9473 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $.01 per share |
| Trading Symbol | WIRE |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
